This is a proposal for the NIMH Collaborative Program on the Psychobiology of Depression ("the Collaborative Depression Study"). The purpose of this application for the Cooperative Agreement is to continue the collaborative effort of a group senior investigators and the NIMH that has functioned smoothly, efficiently, and productively for over a decade. The Cooperative Agreement application requests support for the maintenance of the infrastructure of communication and administration of the Collaborative Depression Study. This infrastructure will ensure continued scientific integrity of the Collaborative Depression Study, protect its sample and data base, and provide ongoing policy and organization for analysis of data and publication of results. The Cooperative Agreement will provide funds to support the Clinical Studies Committee which is the executive body for the Collaborative Depression Study and is vested with responsibility for all major policy and operational decisions. The Cooperative Agreement will also support the Publication Committee which has authority over presentation and publication of all data emanating from more than one center. This committee reviews proposed analyses, abstracts, manuscripts, etc. to assure adequate sharing of data and quality control. Finally, the Cooperative Agreement will support Cluster Committees, which are organized around functional tasks in substantive areas, and serve to plan and execute important activities of the Collaborative Depression Study. These committees are responsible for making recommendations regarding plans and explication of issues, assessment of alternatives and the conduct of data analyses in each area.